Process for treating petroleum oil



Y L. c. HUFF PROCESS FOR TREATING PETROLEUM OIL Feh 2, 1932.

Original Filed May 17. 1922 reame Feb. 2, 1932 'l UNITED STATES. PATENT oFFlcE y LN C. HUFF, OF CHICAGO, ILLINOIS, ASSIGNOR T UNIVERSAL OIL PRODUCTS COI/- PANY, OF CHICAGO, ILLINOIS, A CORPORATION 0F SOUTH DAKOTA PROCESS FOB. TREATING PETROLEUM OIL @riginal application led May 17, 1922, Serial No. 561,585. Divided and this application ledlay 7,

1925, Serial No. 28,539. Renewed February 13, 1929.

This invention relates to improvements in a process for treating petroleum oils, and refers more particularly to afprocess for the conversion of relatively heavy oils into lighter oils such as gasoline and the like.

This application is a division of an applicaltion .tiled by me May 17, 1922, Serial No.

Among the objects of the invention are to provide a process in which the oil 1s heated to a conversion temperature in a heating zone and is passed to a vaporizing stage in whichv the lighter portions are separated ont and pass 0E in vaporous form, the heavier liquid being drawn 0E as residual material.

A further object of the invention is to provide an improved method of. heating the oil and in the arrangement of the apparatus used therefor.

rlhe single figure is a diagrammatic side elevational view of the apparatus with parts and section. o

Referring to' the drawlng, the o1l to be treated is'introduced from any convenient extraneous source through the line 1 controlled by the valve 2 and is passed through the upper layer of tubes 3 positioned near the top of the tube compartment Ztof the furnace 5.

ylhe furnace 5 comprises a combustion chamber 6 in which the burners 7 are situated and the tube compartment 4 lin which the heating coils are positioned. The gases of combustion pass from the chamberv 6 through the ducts 8 Adownwardly through the compartment 4 passing ofi to stack through the flue 9.

The oil after being subjected to the hottest combustion gases entering the tube com- 'positioned in the tube compartment.

pertinent from the combustion chamber, passes down through the line 10 through which it is introduced to one of the lower tubes l11 of the bank of tubes which 'laire 1e oil introduced to the lower tube flows suc? cessively through the continuous coil working its wayupwardly from the cooler por- 'tion of the tube compartment toward the hottestportion which is the top. By the. time f it 'has reached the upper tubes, its temperature has been raised suiiiciently to cause a conversion of the 011, at which time 1t is part of the vaporizing chamber, thus pre venting any collection of carbon about the transfer line at the point at which it enrs the chamber.

The vaporizing chamber preferably comprises a vertical cylindrical chamber mounted within insulated walls 15. At the top is a clean-out manhole 16 and a similar manhole 17 situated at the side. The lower ortion of the chamber is preferably conica ,a relsiduum line 18 controlled by valve 19 being situated at the apex of the cone for drawing oi the heavier unvaporized oil. An emergency residual drawoii' line 20 controlled by valve 21 is inserted'into the side of the chamber to draw o the residual substance should the lower line become clo ged or obstructed.

The insulation about te vaporiyzing chamber consists of materials such as an inside layer of fire felt, an intermediate la er of sponge felt with an outer casing o steel plate. An insulating wall of this character not only serves to more eectively retain the heat of the chamber but absorbs much less of the heat from the process than does a brick or masonry insulating wall.

Near the lower part of theevaporating chamber in the sides of the insulating walls are situated air dempers 22 and similar dam en ers 23 near the top of the chamber. 5:1 manipulating these dempers the cooling air permitted to circulate about the chamber may e controlled and the temperature of the vaporizing chamber likewise re ulated.

rlhe vapors evolved Vin the c amber, pass off through a line 24 controlled by a valve 25 tothe dephlegmator 26 where they are subjected to a refluxing action. After de' isv distillate ows through the line 31 regulated by the valve 32 to the receiving tank 33 where the condensed vapors are collected as liquid distillate.

The gaseous pressure upon the systemis controlled by the relief valve 34 and similar control valves positioned in different portions of the apparatus. The receiver is equipped with a ressure gauge 35, a liquid level gau e 36 and a liquid drawof valve 37.

The re ux condensate separated out in the dephlegmating chamber is returned through the line 38 controlled by valve 39, and is charged with the incoming raw oil to the line 10 where it is subjected with the oil to heat treatment in the heating zone.

When cracking hydrocarbon oil, articularly the more refractory oils, it is o en necessary to-subject them to temperatures having a very deteriorating effect upon the furnace tubes. Thisis particularly true where the combustion gases come in direct contact with the heating tubes and with those tubes which contain the hottest oil. By excess heating, the tubes are not only weakened but are pitted and must be continuously replaced if some provision is not made for tempering the heat of the combustion gases that come in contact with the tubes containing the hottest oil.

As a remedy for these diiiiculties as shown in the drawing, the incoming oil is circulat- `ed in an upper layer of tubes which come in contact with the hottest combustion gases coming through the ducts 8 which connect the combustion chamber 6 with the tube chamber 4. Thus the cool oil is subjected to the hottest furnace temperature, and by circulating the cool oil through this layer of tubes 3 the oil charge is considerably heated prior to its introduction to the main bank of tubes positioned just below the upper preheating tubes. Subsequent to the preheating of the oil, it is passed down through line 10 which is heavily insulated, to the lower tubes in the furnace and its travel is then upwardly throughthe continuous coil'until it Hows through the tubes just below the upper preheating tubes. At-ths point the oil is at its highest temperature, but the tubes containing the hottest oil are shielded from the hottest furnace temthevapor line 24 and after being refluxed and condensed are collected as distillate in 'the receiver. 33. The reflux condensate is returned 'and recycled with the incoming oil charge.

'ber is carefully regulated bythe dampers 22 and 23 which control the circulation of air y within the circular wall 15. Instead of maintaining the oil at a level in the Vaporizing chamber, it is intended that th residuum and heavier unvaporized products be continuously drawn ed so as to prevent the col-v. lection and accumulation of carbonaceous matter in the bottom of the chamber. Where the oil is maintained at a level in the chamber the carbon collects on the side Walls beneath the oil level while above the oil level inthe vapor space there is very little collection of carbonaceous material. Thus by continuously drawing oif the liquid oil and precipitated carbon which is contained therein in a suspended state, the period of operation is considerably lengthened as the process will not have to be slowed down for cleaning.

In the event of an accumulation of carbon in the lower conical portion of the Vaporizing chamber, an alternate emergency line is inserted as shown at 20. The conical .form of the chamber also assists in the iushing out of the carbon and preventing the accumulation of precipitated carbon particles along the side of the walls of the chamber. l

The process may be operated continuously and under a substantial pressure of the generated vapors.l A y By treating mid-continent gas oil-of approximately 32- Baume to temperatures ranging from 700 to 900 F., and pressures of from 50 to 200 pounds,a substantial yield of from 30 to 50% high grade distillate hav'- ing a Baume gravity of from 48 to 52 may be obtained.

It has been found that the vapors in the reaction chamber of a cracking system have a tendency to stratify, the lighter ones going to the top, and the heavier ones collecting y near the bottom of the chamber.- By locating the discharge from the heating tubes in the bottom of thevaporizing stage, the fluid oil which is introduced thereto separates, the vapors therefrom rising through the stratified zone of gaseous vapors, and the residual liquid substance being drawn of from the bottom. of the chamber. The passage of the vapors through the stratified area has a tendency to separate the lighter and heavier vapors conforming with the zones of the stratified area.

By regulating the circulation of air about the chamber, the condensation of the va ors` in' the chamber is controlled. The con ensateproduced therein owing down the sides of the chamber will carry with it any precipitated carbon which has a tendency to collect or adhere to the side of the-chamber. The liquid residue and carbon containing condensate is drawn off to prevent any accumulation of liquid in the bottom of the chamber.

I claim as my invention:

1. A process for cracking hydrocarbon oil consisting in raising the oil to a conversion temperature in a. heating zone, passing the heated fluid oil into an elongated vertical vaporizing stage Where substantial separation of lighter fractions in the form. of vapors takes place, permitting the vapors to have an unobstructed upward travel through the vertical vaporizing stage, preventing the accumulation of precipitated carbon by flushing down the walls of the vaporizingstage with condensate produced Jby circulation of cool air about the vaporizing stage, preventing substantial accumulation of liquid residue in the vaporizing stage and maintaining a regulated vapor pressure during treatment.

2. A process for cracking hydrocarbon oil consisting 1n ralslng the oll to a converslon temperature 1n a heating zone, passing the heated fluid oil to an elongated vertical vaporizing stage and there introducing it nea1` the bottom thereof where substantialvaporization takes place, permitting the vapors to have a substantiallly unobstructed passage upwardly through the vertical vaporizing stage, preventing the accumulation of precipitated carbon by flushing down the walls of the vaporizing stage with condensate produced by circulation of cool air about the vaporizing stage, preventing substantial liquid residue accumulation in the vaporizing v stage, drawing off and condensing the vapors rising to the top of the vaporizing stage, and maintaining regulated pressure upon the oil during treatment.

3. In processes forcracking hydrocarbon oil of the character in which the oil is subjected to a cracking temperature while ad vancing through a heating zone and thence transferred to an enlarged reaction chamber from which vapors and liquid oil are sepa.- rately removed, the improvement which comprises introducing the heated hydrocarbons from the heating zone into the reaction chamber approximately in line with vthe vertical axis thereof to prevent carbon accumulation in the reaction chamber ait the point of introduction of hot oil thereto, and circulating a cooling medium about the walls of the reaction chamber to flush down the walls of the reaction chamber with condensate formed by such cooling. l

4. A process of heating petroleum oils in vtubular coils situated in a furnace which comprises first passing the oil through the part of the coil located in the hottest zone of the furnace, concurrent with the passage of combustion gases inlsaid furnace, then passing the oil directly through a portion of the coil petroleum oil which comprises first passing the oil through a coil at the point of maximum heat of the furnace, passing the oil concurrently with the flow of combustion gases in the furnace, then passing the oil through a portion of the coil situated in a relatively cooler zone of the furnace, passing the oil counter-current to the flow of combustion gases and removing the oil from the coil at a point intermediate the hottest and coolest zone of the furnace.

LYMAN C. HUFF.

situated in the coolest zone of the furnace, 

